1. Field of the Invention
The present invention relates to a method of checking magnetic heads which record magnetic information on a strip-like magnetic material such as a photographic film or the like provided with magnetic recording layers and which read magnetic information, and to a film carrier which positions image frames of a photographic film successively at a predetermined printing position during printing processing and which is equipped with magnetic heads which record magnetic information onto the photographic film and read recorded magnetic information.
2. Description of the Related Art
In recent years, photographic systems have been proposed in which magnetic recording layers are provided at predetermined positions of non-image portions of a photographic film (e.g., a negative film), and information regarding the negative film, information at the time of photographing the images of the respective frames, information at the time of printing the images of the respective frames onto a photographic printing paper, and the like are recorded on the magnetic recording layers. When the images of the respective frames are printed onto a photographic printing paper, the photographic system utilizes the information recorded on the magnetic recording layers. In such a photographic system, a negative film for which developing processing has been completed is not cut into piece negatives of a plurality of frames (e.g., six frames), and instead, is again taken up into a cartridge so that the information recorded on the magnetic recording layers is not damaged.
In order to use, during printing, the information recorded on the negative film, it is necessary to provide a film carrier with functions for recording and reading magnetic information. Thus, many film carriers equipped with magnetic heads for recording and reading magnetic information have been proposed.
The magnetic information recorded on the negative film differs per negative film. Accurate recording of magnetic information and accurate reading of the recorded magnetic information are needed for each negative film.
In order to effect accurate recording and reading of magnetic information, the magnetism generated when the magnetic head for recording (the recording head) records magnetic information must not affect the reading of magnetic information by the magnetic head for reading (the reading head). Further, the recording head and the reading head must respectively be kept in close contact with the magnetic recording layers of the negative film.
Dust, dirt or the like may adhere to the surface of the negative film. When the recording head or the reading head is fit closely to a negative film to which dust or dirt has adhered, the dust or dirt is transferred to the recording head or to the reading head so that the ability of the recording head or the reading head to be fit closely to the magnetic recording layers of the negative film deteriorates. Accurate recording or reading of magnetic information thereby becomes difficult.
It is not easy to visually detect dirt which has adhered to a magnetic head or dirt which has adhered to the surface of a negative film which it is feared will sully a magnetic head. Further, repeatedly confirming whether the recording head accurately recorded information onto the negative film and whether the reading head accurately read the magnetic information of the negative film results in an increase in the number of parts and a deterioration in operational efficiency.
As a result, it is necessary to provide the film carrier with, for example, a reading head which reads the data recorded by the recording head so as to check whether the recording head is operating accurately.
However, the film carrier must frame-advance a negative film in order to print the images recorded on the negative film onto a photographic printing paper, and accordingly, the mounting positions of the reading head and the recording head are restricted. Further, providing a reading head for checking the data recorded by the recording head results in an increase in the number of parts. Moreover, when magnetic information is recorded while the negative film is frame-advanced, the mounting position of the reading head for checking is restricted, and the film carrier becomes larger than necessary.